Because one in three school-aged children are overweight or obese, there is a need to develop and test school-based programming that aims to prevent progression and support remission of childhood obesity (secondary prevention). The proposed study will test a novel elementary school-based, school nurse- directed weight management program that aims to reduce the prevalence of overweight and obesity among 8 to 11 year old children. The 12-month, multi-component intervention for children who are overweight or at risk for overweight will include parents and will target key modifiable diet and activity factors known to be successful in changing long-term energy balance. The program will be offered as a second step of an established school-based body mass index (BMI) screening and parent notification program, held after school and include: 1) quarterly parent/child coaching sessions, 2) twice monthly child groups; 3) a once monthly parent group, and 4) collaboration with health care providers and community-based organizations. Study aims will be accomplished using a randomized controlled trial design, with random assignment of 175 2nd and 4th grade students plus one parent to intervention or attention-only control conditions. The primary aim of this research is to reduce excessive weight gain among 8 to 11 year old children who are overweight or at risk of overweight by increasing healthy dietary practices and physical activity levels and decreasing sedentary practices. Secondary aims will examine the effect of the intervention on the dietary, physical activity and sedentary practices of children and on family lifestyle practices overseen by parents. Measures for children will include height and weight, dietary intake measured by 24-hour dietary recall, child activity levels measured by accelerometer, health-related quality of life and psychosocial factors. Parent measures will include height and weight, parental dietary and activity practices and psychosocial and environmental mediators at the family level. Process measures will assess program implementation and include measures of fidelity, dose, reach and context. Collaboration with key stakeholders representing school nursing practice, health insurers, health providers and community programming, as well as prospective economic analyses of intervention effectiveness will support translation of this work into sustainable school practice. It is hypothesized that relative to the control condition, children receiving the intervention will have significantly lower body mass index, following implementation of the 12-month intervention, controlling for baseline values.